Accordingly, the motives which the artifices of France now put in operation, in order to detach him from the Austrian alliance, and to induce him to lay down his arms, were drawn entirely from political considerations. It was not without a selfish object that Mazarin had so far overcome his jealousy of the growing power of the Swedes, as to allow the French to accompany them into Bavaria. His intention was to expose Bavaria to all the horrors of war, in the hope that the persevering fortitude of Maximilian might be subdued by necessity and despair, and the Emperor deprived of his first and last ally. Brandenburg had, under its great sovereign, embraced the neutrality; Saxony had been forced to accede to it; the war with France prevented the Spaniards from taking any part in that of Germany; the peace with Sweden had removed Denmark from the theatre of war; and Poland had been disarmed by a long truce. If they could succeed in detaching the Elector of Bavaria also from the Austrian alliance, the Emperor would be without a friend in Germany and left to the mercy of the allied powers.
Ferdinand III. saw his danger, and left no means untried to avert it. But the Elector of Bavaria was unfortunately led to believe that the Spaniards alone were disinclined to peace, and that nothing, but Spanish influence, had induced the Emperor so long to resist a cessation of hostilities. Maximilian detested the Spaniards, and could never forgive their having opposed his application for the Palatine Electorate. Could it then be supposed that, in order to gratify this hated power, he would see his people sacrificed, his country laid waste, and himself ruined, when, by a cessation of hostilities, he could at once emancipate himself from all these distresses, procure for his people the repose of which they stood so much in need, and perhaps accelerate the arrival of a general peace? All doubts disappeared; and, convinced of the necessity of this step, he thought he should sufficiently discharge his obligations to the Emperor, if he invited him also to share in the benefit of the truce.
The deputies of the three crowns, and of Bavaria, met at Ulm, to adjust the conditions. But it was soon evident, from the instructions of the Austrian ambassadors that it was not the intention of the Emperor to second the conclusion of a truce, but if possible to prevent it. It was obviously necessary to make the terms acceptable to the Swedes, who had the advantage, and had more to hope than to fear from the continuance of the war. They were the conquerors; and yet the Emperor presumed to dictate to them. In the first transports of their indignation, the Swedish ambassadors were on the point of leaving the congress, and the French were obliged to have recourse to threats in order to detain them.
The good intentions of the Elector of Bavaria, to include the Emperor in the benefit of the truce, having been thus rendered unavailing, he felt himself justified in providing for his own safety. However hard were the conditions on which the truce was to be purchased, he did not hesitate to accept it on any terms. He agreed to the Swedes extending their quarters in Suabia and Franconia, and to his own being restricted to Bavaria and the Palatinate. The conquests which he had made in Suabia were ceded to the allies, who, on their part, restored to him what they had taken from Bavaria. Cologne and Hesse Cassel were also included in the truce. After the conclusion of this treaty, upon the 14th March, 1647, the French and Swedes left Bavaria, and in order not to interfere with each other, took up different quarters; the former in Wuertemberg, the latter in Upper Suabia, in the neighbourhood of the Lake of Constance. On the extreme north of this lake, and on the most southern frontier of Suabia, the Austrian town of Bregentz, by its steep and narrow passes, seemed to defy attack; and in this persuasion, the whole peasantry of the surrounding villages had with their property taken refuge in this natural fortress. The rich booty, which the store of provisions it contained, gave reason to expect, and the advantage of possessing a pass into the Tyrol, Switzerland and Italy, induced the Swedish general to venture an attack upon this supposed impregnable post and town, in which he succeeded. Meantime, Turenne, according to agreement, marched into Wuertemberg, where he forced the Landgrave of Darmstadt and the Elector of Mentz to imitate the example of Bavaria, and to embrace the neutrality.
And now, at last, France seemed to have attained the great object of its policy, that of depriving the Emperor of the support of the League, and of his Protestant allies, and of dictating to him, sword in hand, the conditions of peace. Of all his once formidable power, an army, not exceeding 12,000, was all that remained to him; and this force he was driven to the necessity of entrusting to the command of a Calvinist, the Hessian deserter Melander, as the casualties of war had stripped him of his best generals. But as this war had been remarkable for the sudden changes of fortune it displayed; and as every calculation of state policy had been frequently baffled by some unforeseen event, in this case also the issue disappointed expectation; and after a brief crisis, the fallen power of Austria rose again to a formidable strength. The jealousy which France entertained of Sweden, prevented it from permitting the total ruin of the Emperor, or allowing the Swedes to obtain such a preponderance in Germany, as might have been destructive to France herself. Accordingly, the French minister declined to take advantage of the distresses of Austria; and the army of Turenne, separating from that of Wrangel, retired to the frontiers of the Netherlands. Wrangel, indeed, after moving from Suabia into Franconia, taking Schweinfurt, and incorporating the imperial garrison of that place with his own army, attempted to make his way into Bohemia, and laid siege to Egra, the key of that kingdom. To relieve this fortress, the Emperor put his last army in motion, and placed himself at its head. But obliged to take a long circuit, in order to spare the lands of Von Schlick, the president of the council of war, he protracted his march; and on his arrival, Egra was already taken. Both armies were now in sight of each other; and a decisive battle was momentarily expected, as both were suffering from want, and the two camps were only separated from each other by the space of the entrenchments. But the Imperialists, although superior in numbers, contented themselves with keeping close to the enemy, and harassing them by skirmishes, by fatiguing marches and famine, until the negociations which had been opened with Bavaria were brought to a bearing.
The neutrality of Bavaria, was a wound under which the Imperial court writhed impatiently; and after in vain attempting to prevent it, Austria now determined, if possible, to turn it to advantage. Several officers of the Bavarian army had been offended by this step of their master, which at once reduced them to inaction, and imposed a burdensome restraint on their restless disposition. Even the brave John de Werth was at the head of the malcontents, and encouraged by the Emperor, he formed a plot to seduce the whole army from their allegiance to the Elector, and lead it over to the Emperor. Ferdinand did not blush to patronize this act of treachery against his father's most trusty ally. He formally issued a proclamation to the Bavarian troops, in which he recalled them to himself, reminded them that they were the troops of the empire, which the Elector had merely commanded in name of the Emperor. Fortunately for Maximilian, he detected the conspiracy in time enough to anticipate and prevent it by the most rapid and effective measures.
This disgraceful conduct of the Emperor might have justified a reprisal, but Maximilian was too old a statesman to listen to the voice of passion, where policy alone ought to be heard. He had not derived from the truce the advantages he expected. Far from tending to accelerate a general peace, it had a pernicious influence upon the negociations at Munster and Osnaburg, and had made the allies bolder in their demands. The French and Swedes had indeed removed from Bavaria; but, by the loss of his quarters in the Suabian circle, he found himself compelled either to exhaust his own territories by the subsistence of his troops, or at once to disband them, and to throw aside the shield and spear, at the very moment when the sword alone seemed to be the arbiter of right. Before embracing either of these certain evils, he determined to try a third step, the unfavourable issue of which was at least not so certain, viz., to renounce the truce and resume the war.